Probably it is a bug but I would not rely on the standard disc elements.
You could use CSS ::before pseudo-element instead. It is much more configurable and is fully under your control.
$("#a").click(function() {
$("#a").addClass('blue');
});
ul li {
color: red;
list-style-type: none;
margin-left: 2em;
}
ul li::before {
content: "?";
}
.blue {
color: blue;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<ul>
<li id="a">a</li>
<li id="b">b</li>
<li id="c">c</li>
</ul>
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